high-flow, quiet mufflers...suggestions?

[com_mako]

anyone try magnaflow exhaust ???

[kro10000]

Threads like this are opinionated, theory, and useless BS unless you confirm and prove before and after data results on the dyno for your performance mods. Y'all know that.

Right well as I have only the seat-of-the-pants dyno to use I don't think that before and after numbers gonna be possible. FWIW the pipes that really make or break your torque numbers are the header pipes, these are what create the exhaust scavenging effect that effects torque. Afterwards as long as the exhaust doesn't impede the exhaust scavenging, the best possible scenario is to remove all exhaust as fast as possible, which higher back pressure impedes. So you don't want to go with exhaust pipe that is too big, so that the exhaust has time to cool and become dense, which makes it more difficult to remove from the pipes.

 

More exhaust backpressure means more power lost pushing it out the tailpipe.

[Comanche County]

I'm with Eagle, every performance muffler I've put on any vehicle has hurt low end torque, gas mileage and around town drivability. I know this is a vast generality but they only help if you've got the engine throttled wide open IMHO.

[offroader461]

anyone try magnaflow exhaust ???

 

magnaflow's suck on anything less than a v8....i had one for about 6month or so and it wasnt any better than stock

[Comanche County]

I put a magnaflow on a 5.9 ZJ. Sounded great, little more rumble than stock but hurt low end torque. Gotta another 5.9 ZJ now with a 40 series flowmaster, louder than the magnaflow and hurt the low end take off power even more...I keep it just because it sounds cool.

[JeepcoMJ]

put the flowmaster on.

 

 

can't deal with the drone.

 

put a straight pipe on. less of a drone than the flowmaster.

 

 

I can NOT have ANY loud, constant "throaty" noises that last for any extended period of time. I will NOT put a stock muffler on, for fact that it will negatively effect the performance of my motor. i need a good balance in back pressure, and something quiet as hell.

[HOrnbrod]

put the flowmaster on.

 

can't deal with the drone.

 

put a straight pipe on. less of a drone than the flowmaster.

 

I can NOT have ANY loud, constant "throaty" noises that last for any extended period of time. I will NOT put a stock muffler on, for fact that it will negatively effect the performance of my motor. i need a good balance in back pressure, and something quiet as hell.

 

Hell ain't quiet mate. What "performance" are you talking about? Just the Borla?

[JeepcoMJ]

put the flowmaster on.

 

can't deal with the drone.

 

put a straight pipe on. less of a drone than the flowmaster.

 

I can NOT have ANY loud, constant "throaty" noises that last for any extended period of time. I will NOT put a stock muffler on, for fact that it will negatively effect the performance of my motor. i need a good balance in back pressure, and something quiet as hell.

 

Hell ain't quiet mate. What "performance" are you talking about? Just the Borla?

 

 

stated multiple times.

 

.030 bore, srt4 injectors, 2001+ intake manifold, 62mm tb, borla header, competition cam.

 

not stock by any means whatsoever. the motor is out of my "utility build" comanche. has 12,000 miles on it.

 

I have been having issues with my inner cochlea and some sounds I just cannot abide. your muffler sounds like the best bet, but I am not prepared to wait multiple weeks to get it...i need this fixed yesterday (migranes just from the noise driving the jeep...no leaks from exhaust, double checked)

 

-Pat

[HOrnbrod]

Sorry I didn't memorize all the mods on your engine. Can understand the problems you have with the droning; I think it's a header thing. On mine, it hit a harmonic resonant frequency from about 55-65 MPH that drove me nuts. It would vibrate the fillings in your teeth. Below or above that range all was golden. I was lucky that my friend had a muffler shop and it took some time and experimentation with several configurations to work it out w/o losing any gain from previous dyno runs. All I can say is what worked for me. Droning and resonance in the exhaust system is a fairly common problem with strokers and is sometimes hard to solve. Good luck.........

[SoloCamo]

put the flowmaster on.

 

can't deal with the drone.

 

put a straight pipe on. less of a drone than the flowmaster.

 

I can NOT have ANY loud, constant "throaty" noises that last for any extended period of time. I will NOT put a stock muffler on, for fact that it will negatively effect the performance of my motor. i need a good balance in back pressure, and something quiet as hell.

 

Hell ain't quiet mate. What "performance" are you talking about? Just the Borla?

 

 

stated multiple times.

 

.030 bore, srt4 injectors, 2001+ intake manifold, 62mm tb, borla header, competition cam.

 

not stock by any means whatsoever. the motor is out of my "utility build" comanche. has 12,000 miles on it.

 

I have been having issues with my inner cochlea and some sounds I just cannot abide. your muffler sounds like the best bet, but I am not prepared to wait multiple weeks to get it...i need this fixed yesterday (migranes just from the noise driving the jeep...no leaks from exhaust, double checked)

 

-Pat

 

I highly suggest running a Magnaflow Turbo muffler. :thumbsup:

 

Got mine for around $50 and running it with a hi-flo cat, ford 19lb injectors, and a heatshielded/cutout airbox with a K&N drop in and it definitely woke up even my practically stock motor which is mostly due to removing the restrictive muffler for the previous mods listed (which are mere jokes in comparison to your motor)

 

The magnaflow does not drone on the highway, and to be quite honest, even with a hi-flow cat is only mild at best around town/daily driving and is hardly louder than stock. However, if you put your foot down, it sounds like a completely different engine is under the hood and mid-top end power has definitely improved, even on my auto Renix with its wonderful 5k redline.

 

Again, the magnaflow is highly recommended by me. Dynomax is good as well with similar characteristics but I personally enjoy the magnaflows's sound a bit better and there was less drone on the highway in comparison.

 

Keep in mind, besides the hi-flow cat, maganaflow muffler, slight intake mods and injectors, my 4.0L is stock, so with your setup I'd imagine it would really sound great and remove that restriction on your power especially seeing what it did for me.

 

Either way, let us know and get some sound clips if possible! Headers and a new downpipe are next on my list for my renix!

 

__

 

Not to go off topic, but expand on those SRT-4 injectors? I always thought the 24lb ford were ideal for a setup similar to yours and to be quite frank didnt even know the srt-4 were swappable. I used to run a 2003 srt-4, fun car, but too many tickets :chillin:

[JeepcoMJ]

 

Not to go off topic, but expand on those SRT-4 injectors? I always thought the 24lb ford were ideal for a setup similar to yours and to be quite frank didnt even know the srt-4 were swappable. I used to run a 2003 srt-4, fun car, but too many tickets :chillin:

 

 

thanks for your advice.

 

the srt4 injectors have a few more pounds than stock, but with a multiple port spray pattern, which allows better atomization.

 

this is a '99 cherokee, my comanche is also '99 cherokee conversion...the srt4 injectors were direct plug and play. you'd have to modify wires to make them work on anything '96 and older.

[SoloCamo]

 

Not to go off topic, but expand on those SRT-4 injectors? I always thought the 24lb ford were ideal for a setup similar to yours and to be quite frank didnt even know the srt-4 were swappable. I used to run a 2003 srt-4, fun car, but too many tickets :chillin:

 

 

thanks for your advice.

 

the srt4 injectors have a few more pounds than stock, but with a multiple port spray pattern, which allows better atomization.

 

this is a '99 cherokee, my comanche is also '99 cherokee conversion...the srt4 injectors were direct plug and play. you'd have to modify wires to make them work on anything '96 and older.

 

Good to know, I appreciate it. The Ford 19lbs have worked pretty well for me. 4 port spray pattern and very slightly higher flow rate (18.6 vs 19lb). To be quite honest, if anything I run a bit lean at times when it warms up here (Florida). Not to hijack the thread here, but is there a mid range injector? 24lbs is obviously going to be flooding my motor, but I still seem a bit lean on the 19lbs with my intake/exhaust work.

[HOrnbrod]

21# injectors and/or an adjustable MAP should work for you.

 

Model Year, .....Part #, .....Colour, .....Fuel Pressure, ..Static Flow,

'87-'90, ........53003956, ...Black, ......39psi, ..........18.6lb/hr

'91-'93, ........33007127, ...Brown, ......39psi, .........21.0lb/hr

'94-'95, ........53030343, ...Tan, ........39psi, ..........21.0lb/hr

'96-'99, ........53030778, ...Grey, .......49psi, ..........23.2lb/hr

'00-'01, ........04854181, ...Blue tip, ...49psi, ..........22.5lb/hr

 

The injector flow rate varies as the square root of the pressure drop across the injector. The stock '91-'95 4.0 injectors are rated at 22lb/hr @ 43psi fuel pressure, so at 39psi they flow ( sq. rt.(39/43) x 22.0 = 21.0 ).

 

For stock/modified 4.0 engines or stroker build-ups the following injectors can be installed. The flow rates are:

 

Ford Motorsport 19.0lb/hr @ 39psi (Part no. FMS-M9593-C302)

Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)

Ford Motorsport 30.0lb/hr @ 39psi (Part no. FMS-M9593-B302)

Chevy LT1 24.0lb/hr @ 43.5psi (Part no. 1712424

Chevy LT4 28.0lb/hr @ 43.5psi (Part no. 17124251)

'98 Chevy LS1 25.2lb/hr @ 58.0psi (Part no. 12533952)

'99-'00 Chevy LS1 26.2lb/hr @ 58.0psi (Part no. 12456154)

'01-'02 Chevy LS1/LS6 28.6lb/hr @ 58.0psi (Part no. 12482704)

Accel 19.2lb/hr @ 44.1psi (ACC-150119)

Accel 21.1lb/hr @ 44.1psi (ACC-150121)

Accel 24.4lb/hr @ 44.1psi (ACC-150124)

Accel 25.6lb/hr @ 44.1psi (ACC-150126)

Accel 29.4lb/hr @ 44.1psi (ACC-150130)

[dakal]

wow! now thats an answer